A tyre of a vehicle wheel comprises notably a tread designed to be in contact with the ground when the vehicle moves. To reduce the rolling resistance of the tyre, it is known practice to add a silica filler to the rubber mixture forming the tread. However, the high silica content that results in the tread makes it a particularly poor conductor of electricity. However, the tyre usually also has the function of placing the vehicle in electrical contact with the ground in order to prevent the build-up of static electricity on board.
In these conditions, in order to maintain an electrical connection between the vehicle and the ground, it is known practice, for example from document FR-2 775 220 to place in the tread an insert comprising a rubber mixture that is a good conductor of electricity. For this purpose, the tread is produced by extrusion of the material that is a poor conductor of electricity and an insert formed of an electrically conductive mixture is inserted by coextrusion into the extrusion channel.
A rubbery material that is a poor conductor of electricity is frequently understood to be a rubber-based material having a resistivity of more than or equal to 108 ohm/cm. Similarly, a rubbery material that is electrically conductive is understood to be a rubber-based material having a resistivity of less than 106 ohms/cm. The function of the insert is to conduct the electrical charges from the radially inner portion of the tread to the radially outer portion in contact with the ground.
It is also possible to manufacture the tread by continuously winding rubber plies of variable width as is described in the publication WO 2009/131578 of the applicant.
However, this document does not describe the means used to place an insert into the tread.